The present invention pertains generally to the art of pneumatic tire testing systems adapted for indoor use. More particularly, the present invention relates to a new and improved device for dispersing a powder substance onto a wear surface during indoor tirewear testing in order to prevent particle build-up or gumming on the outer surface of the tire and wear surface.
A conventional pneumatic tire for cars, trucks, etc. is generally fabricated from elastomeric materials, such as cured rubber products. After the pneumatic tire is mounted on a vehicle, it typically undergoes compressive, tensile and shearing forces as it travels along a road surface. Such forces will inevitably cause particles to be worn from the tire tread and oils to be released from the rubber material. Over an extended period of time, the tire will wear to a point that it will have to be replaced.
Tire manufacturers often test their tires in order to determine how the tires will perform under typical and/or extreme driving conditions. In addition, tire testing is helpful for detecting manufacturing problems. The information resulting from tire testing is important for learning how tires can be improved in terms of safety, length of life, and performance. However, it is difficult to conduct reliable tire testing unless the tires are actually put on a vehicle and driven on a variety of surfaces for an extended period of time. Such testing is obviously not practical. Thus, manufacturers have developed indoor or laboratory tire testing systems which attempt to recreate and expose tires to actual driving conditions.
Laboratory tire wear testing is a relatively new field of technology. In a typical indoor testing process, a tire is loaded against a rotating road wheel which has an abrasive surface attached thereto. The tire and rotating road wheel are designed to simulate actual driving conditions. As the road wheel rotates against the tire, tire particles and oils are released and tread rubber is slowly worn away.
Under actual driving conditions a vehicle moves relative to the road surface. Thus, the released particles are immediately dispersed away from the tire and, therefore, have negligible influence on the tire performance. In contrast, during indoor tire testing, the tire is loaded against the road wheel and rotated at a fixed reference point. As a result, the worn particles circulate and accumulate around the surfaces of the tire and abrasive surface. The particles have oils which cause them to become soft and sticky. Thus, the released materials adhere to the tire tread and/or abrasive surface, masking the performance of the tire tread and hindering the acquisition of accurate data.
One known solution for preventing the abraded gummy rubber particles from adhering to the tire and/or abrasive surface is to introduce a powder substance onto the abrasive surface of the rotating road wheel as the tire is being tested. Any variety of powders may be used, such as fluidized talcum powder. The powder, when dusted or sprayed onto the wear surface, will adhere to or absorb the released particles and minimize the occurrence of abrading and gumming.
Fluidized powder spray equipment designed specifically for minimizing gumming and abrading is known and commercially available. However, known powder spraying devices suffer from a number of shortcomings. First, they are unable to achieve a consistent and controlled application of the powder to the abrasive surface. Second, they do not collect excess powder before it is caught in the turbulent air stream of the rotating wheel and dispersed throughout a large working environment. Third, they are not capable of conducting wear testing in both directions of rotation. Finally, they do not allow for the powder dispensing nozzle to be disposed at different positions relative to the road wheel.
Accordingly, a need exists to provide a powder dispensing/collecting device for indoor tire testing applications which overcomes the foregoing problems and others.
In accordance with one aspect of the present invention, a powder dispensing and collection device for testing of pneumatic tires includes a first housing having an open end facing an abrasive surface of an associated road wheel. A second housing, which is at least partially enclosed by the first housing, defines a dispensing chamber. The second housing has an open end facing the abrasive surface of the road wheel. At least one interior surface of the first housing and at least one exterior surface of the second housing define a vacuum collection chamber. A dispensing mechanism is operatively connected to the second housing and is located within the dispensing chamber. The dispensing mechanism is configured to apply a media to the abrasive surface.
In accordance with another aspect of the present invention, a testing device for pneumatic tires includes a road wheel having an outer abrasive surface. A first housing encloses a vacuum collection chamber. The first housing has an open end adjacent the abrasive surface of the road wheel. A second housing is disposed adjacent the abrasive surface of the road wheel and defines a dispensing chamber. The second housing has an open end facing the abrasive surface. A dispensing mechanism is operatively connected to the second housing and is located within the dispensing chamber. The dispensing mechanism is configured to apply an absorbent media to the abrasive surface of the road wheel.
In accordance with another aspect of the present invention, a method for dispersing and collecting an absorbent media during testing of a pneumatic tire includes loading a tire against an abrasive surface of a road wheel and positioning an inner housing adjacent the abrasive surface of the road wheel and within an outer housing. Apply a media to the abrasive surface of the road wheel via a spray nozzle which is disposed within a dispensing chamber defined by the inner housing. Excess absorbent media and worn particles which fall from the abrasive surface and surrounding area are vacuumed into a vacuum collection chamber which is enclosed by the second housing. The excess absorbent media and worn particles are transferred from the vacuum collection chamber to at least one vacuum duct communicating with the vacuum collection chamber.
One advantage of the present invention is the provision of a dispensing/collection device for indoor testing of pneumatic tires which minimizes the occurrence of particle build-up and gumming.
Another advantage of the present invention is the provision of a dispensing/collection device for indoor testing of pneumatic tires which vacuums and removes excess powder during testing which would otherwise be dispersed throughout a large working environment.
Another advantage of the present invention is the provision of a dispensing/collection device for indoor testing of pneumatic tires having a stagnant air column through which a powder stream travels before being applied to a road wheel, thereby allowing for a more consistent and controlled application of the powder to an abrasive surface of the road wheel.
Another advantage of the present invention is the provision of a dispensing/collection device for indoor testing of pneumatic tires having adjustable shrouds which enable an operator to regulate the position of a vacuum collection chamber relative to a road wheel and the suction force of the device.
Yet another advantage of the present invention is the provision of a dispensing/collection device for indoor testing of pneumatic tires having a nozzle that can effectively apply a powder to a testing surface at a distance relatively far away from the testing surface.
Still another advantage of the present invention is the provision of a dispensing/collection device for indoor testing of pneumatic tires that is capable of effectively conducting wear testing in either direction of rotation.
Still other benefits and advantages of the invention will become apparent to those skilled in the art upon reading and understanding the following detailed specification.